


A Necessary Detention

by Chaotic_Smutty (Anna_Hopkins)



Category: Harry Potter - J. K. Rowling
Genre: Alternate Universe - Canon Divergence, Duelling, Gratuitously Hot Voldemort, Hogwarts Seventh Year, M/M, Magically Powerful Harry Potter, Oral Sex, Plot What Plot/Porn Without Plot, Professor Tom Riddle, Prompt Fill, Teacher-Student Relationship
Language: English
Status: In-Progress
Published: 2020-03-12
Updated: 2020-02-13
Packaged: 2021-02-27 19:20:26
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,512
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22690894
Author URL: https://archiveofourown.org/users/Anna_Hopkins/pseuds/Chaotic_Smutty
Summary: More and more lately, Harry'd begun to wonder if he wouldn't rather have the Defense curse back. Leave it to the least interesting, most normal person to have filled the post in years -- one 'Thomas Riddle', currently -- to find the loophole in the curse and stay for more than one term.
Relationships: Harry Potter/Tom Riddle | Voldemort
Comments: 15
Kudos: 293
Collections: Harry Potter





	A Necessary Detention

Harry sighed under his breath as he took his usual seat at the front row of the Defense classroom, dreading the start of the day. He was the first to arrive, as usual, which gave him ample time to arrange his quill, ink and parchment, then rearrange them several times in a vain attempt to alleviate his frustration.

More and more lately he'd begun to wonder if he wouldn't rather have the Defense curse back; the four years of variously incompetent, cursed, possessed, and mad wizards he'd started with had been an annoyance at the time, but now felt more nostalgic than anything. Leave it to the least interesting, most normal person to have filled the post in years -- one 'Thomas Riddle', currently -- to find the loophole in the curse and stay for more than one term. He just  _ changed his name _ at the end of each year! Tom Marvolo Riddle to Tom Riddle to Thomas Riddle, each of them magically different enough from the last to count as a whole new wizard.

And so, DADA had gone from 'exciting but disorganized' to 'neat but dull', like any other class. Harry thumped his head down in his arms, on the desk, and stared wearily at the clock over the door: ten more minutes before class began. The novelty of a 'normal' professor wore off after the first year; and as Harry grew more agitated, by his sixth year, he'd begun to act out.

Now, more than a year since that development, it had become practically routine to interrupt Riddle's otherwise-interesting stories with complaints, criticism, and pointed questions, phrased just politely enough to be above punishment. Harry took some enjoyment out of flustering the admittedly-handsome professor, with his lush salt-and-pepper hair and his graceful walk and his clever comebacks that melted off his tongue like honey--

_ Oh, hell, I'm thinking about it again. _ Harry closed his eyes, pressing his forehead into the wooden surface of the desk.  _ Don't antagonize the professor, don't antagonize the professor-- _

Okay, Harry  _ might _ have developed a thing for Professor Riddle just like everyone else had, at the beginning. But while they'd gotten over it, Harry... hadn't. Merlin, why had he made such a habit of sitting in the front of the room? He couldn't go sit in the back now, not after two years in this spot, or Riddle would eye him curiously all lecture and Harry wouldn't be able to keep from staring back and memorizing every detail of that fanciable face--

Ugh. He really didn't know what to do.

Harry hid away his frustration, before class began.  _ I can do this, _ he told himself,  _ I can keep my mouth shut for once. _ But clearly, he couldn't, for halfway through the allotted hour, Harry couldn't resist commenting on Riddle's story about the Egyptian tomb and the hexed treasure chest. And he might have been snarkier than usual, about it; might have insinuated Riddle was a fool for falling for the obvious trap with more bite in his tone than usual.

"Detention, Mr. Potter, for your disrespect," Riddle snapped out, looking supremely pleased with himself for finally getting sufficient sass from Harry to justify it.

_ Well, shit. _

Harry had blown it. And all the detentions he could think of involved  _ blowing, _ too, and now he couldn't focus well enough to take notes. He shifted in his seat, anxious for the hour to end.

"Class dismissed," said Riddle eventually, having concluded his story while Harry was busy failing to focus. "Ah, Mr. Potter," he added in afterthought, "stay behind."

Harry suddenly felt very faint, and stifled a whimper. That was exactly the phrase he'd been (trying not to be) daydreaming about.  _ Merlin help me. _

The last of his classmates departed the room, and Riddle closed and locked the door. Harry swallowed around the lump in his throat, cheeks heating, because this too was precisely in line with his -- ahem -- fantasies.

Then Riddle turned back to him, and his expression was full of such sincere concern that it threw Harry for a loop. "Mr. Potter," said the professor, "are you quite all right? That outburst was uncharacteristic of you."

He sounded so  _ worried _ about Harry that it was painful -- his stomach clenched with guilt over the assumptions he'd been making. Riddle had asked him to stay behind because he  _ cared _ \-- he had locked the door as a privacy measure, given the personal nature of the question. Harry swallowed, averting his eyes to the floor. "I'm sorry, sir," he said, with genuine remorse. "It's just been --"  _ agony trying not to get hard during class -- _ "stressful, with NEWTs coming up, and I haven't been getting much sleep,"  _ what with all the frustrated wanking. _ "Usually I duel it out with Ron and Mione and Nev, but they're busy studying too."

And this was true; with Quidditch season over, and his friends embroiled in study for their more academically-minded NEWTs (even Ron, surprisingly, and possibly because he wanted an excuse to spend time with Hermione), Harry  _ had _ gotten rather frustrated with the absence of an outlet for his abundant magic. That problem was in fact more persistent and affecting than Harry's uncontrollable fantasies about his professor, little as he dared to acknowledge either.

Riddle seemed to understand exactly what Harry meant about the duelling without him needing to get specific. "It is important to have a place and time to let off steam, yes," he agreed, bracing one hand beside Harry's inkwell on the desk. "In truth," the professor confided, "your detention this evening will serve that purpose -- addressing the root cause of your behavior, rather than punishing you for the symptoms."

"...Sir?" Harry didn't quite understand. (His mind was taking him in a different direction from what Riddle probably meant.)

The professor stepped back from the desk. "Come, let me show you the place I have in mind," he said. "There is a hidden door beside the door to my office; you will be able to see it now that I have mentioned its existence." Harry glanced over, and true enough, a second door -- made of stone, rather than wood -- now stood beside the office door. He raised his eyebrows, surprised, and nodded.

"Excellent." Riddle smiled benevolently down at Harry (he was so  _ wondrously _ tall --  _ stop thinking about that, damn it). _ "Follow me; I am sure it will surprise you." The professor made for the door, and Harry hefted up his satchel to follow, feeling rather nervous.

The door opened on its own as Harry and Riddle got close enough to it; crossing the threshold, Harry blinked, surprised, and nearly stopped short with the older wizard behind him.

The cavernous room they had entered was as unlike any other room in Hogwarts as any Harry had seen -- barring, perhaps, the Chamber of Secrets. Illuminated by a general, diffuse glow, the stone expanse was roughly circular, with a deep groove cut into the floor in a more perfect circle shape. Every sound echoed twice; it was deathly silent but for the sounds of their presence, more like a tomb than a room at all. Unbidden, a shiver ran down Harry's spine at the thought; he clenched his hand around the strap of his satchel, looking to the professor for an explanation. "...Where are we, sir?"

"This is Hogwarts' duelling hall," Riddle told him. "In my day, we had weekly exhibitions and student-led tournaments here, after dinner. The Headmaster's first act on gaining his position was to end the practice, unfortunately, but it means the hall is now free for us to use as we please."

"Us?" Was Riddle saying they were going to duel..?

He flinched, surprised, as the professor laid a hand lightly on his shoulder. "Us, indeed. If you are not opposed to the idea, I believe a few rounds would be a welcome release for us both."

Harry blinked. Had that been..? No, certainly not. "I'd love to," he said quickly. "I'm just, er, surprised -- you never do demonstrations in class yourself. We figured, well..."

"That I was too weak to demonstrate?" Riddle's eyes fairly glittered with mirth; the corners of his lips turned up in a smirk. "On the contrary, Harry, I greatly enjoy feats of magic, duelling especially; but the general student population would be unable to match me, and so I... restrain the urge."

_ Okay, it's definitely not just me projecting, _ Harry thought.  _ That was absolutely innuendo. _ The way Riddle spoke about 'urges' made it sound almost  _ primal, _ and Harry hadn't missed the way he had switched to his first name with audible relish.

He licked his lips, fingering his wand in his pocket, and wondered. "I've... I've got a free period right now," Harry confessed, trying not to sound too eager (and probably failing). "If, erm, if you want to." His voice was betraying him, he thought, with how breathily the words came out. But Harry hadn't had a duel for more than two weeks, and the dry spell was  _ killing him,  _ and Riddle was offering to help him out --  _ good Godric now  _ **_I'm_ ** _ phrasing things weirdly. _

Riddle heard the need in his tone, too, it seemed; for there was an interested gleam in his dark eyes now, the smirk on his lips turned a different sort of playful, as he strode forward to enter the duelling circle and swept around in a whorl of black robes to face Harry again, wand drawn. He'd always worn more fitted robes than was typical for professors. Now, Harry wondered if they were meant to be duelling robes, of a sort. "Join me in the circle," Riddle said, more an order than a request. Harry complied immediately, withdrawing his wand from its holster as he crossed the line. The familiar euphoria of imminent combat washed over him, a noticeable lightening of his step, and Harry couldn't help the slow smile that spread across his face any more than he could help the way every muscle tensed and relaxed in anticipation.

At the far end of the circle, Riddle looked to be settling into the same state. The unassuming professor's smirk had widened into a smile to match Harry's; and then he seemed to shake a layer of something invisible from his shoulders, and Harry sucked in a gasp as a cool breeze swept across the space between them. "You have it too," he breathed, surprised and delighted. "Battle aura."

It was the mark of a strong wizard, he’d learned -- the pressure they exerted on a space when they let their magic loose. Dumbledore and Grindelwald had it; Voldemort had had it when he fought Dumbledore in the Ministry two years ago; Harry had thought himself the only other wizard on that list, but now he knew Professor Riddle did too.

Like shedding a heavy cloak, he unburdened himself of the restraints kept on his magic for so long. Riddle's eyes widened, and his smile bared his neat white teeth.

"Do you challenge me, Harry?" Riddle took several steps forward, his aura washing over Harry like a fine mist.

"I challenge you, Professor Riddle," Harry agreed, matching the older wizard in the opening stance of a formal duel. "What are your terms?" For the first time, he genuinely wished to observe the traditions of duelling that he'd once thought tedious - wanted to show respect for his opponent, this time. It felt  _ right, _ where it hadn't when facing his friends.

Riddle's voice was melodic, playful, and perhaps a bit overdramatic, but Harry liked the drama. "No fatal attacks, magical or physical," he declared, "nor permanent injury. All else is fair game."

_ Is he permitting what I think he's permitting? _ Harry wondered, exhilarated. "I agree to your terms," he called out. "We duel to our satisfaction, then?" Because he didn't want to just duel to a standstill; this was /more/ than that, he could feel it in his bones.

"To our satisfaction," Riddle agreed. "And call me Tom."

Then he changed his stance, and they began.

"Harry and Riddle have been in there a while," Hermione mused, eyeing the door to the classroom. "Do you think we should keep waiting for him?" It had been fifteen minutes already.

"Nah," Ron shrugged. "Maybe they're working out their differences. Rather not wait around and find out."

Goodness knew their friend had unresolved emotions toward the professor, and only Merlin knew why. A lot of them. In fact...

"You don't think they're kissing in there, do you?" Ron asked suddenly, dawning horror on his face.

Hermione laughed, hitting him on the arm. "Don't be  _ silly, _ Ron. Riddle isn't that kind of person -- even if Harry is," she acknowledged, tilting her head. "The professor makes a point of being professional. When has he ever even  _ bent _ the rules? He's practically a Hufflepuff." She shook her head, amused at the very idea of it. "Them kissing is about as likely as Riddle casting Dark magic."

Sweat dripped down Harry's forehead and into his eyes, briefly obscuring his vision as he rolled into a crouch to dodge a sickly yellow curse. That was  _ definitely _ Dark -- a Bone-breaker, Harry thought, as he leaped closer, twisting to narrowly avoid several red and purple spells that flew from Riddle's wand in rapid succession. The professor was working up to a spell chain; if Harry could just break his rhythm --

"Confringo," Harry whispered, aiming his wand at the floor. Riddle danced out of the way, emerging through the cloud of resultant dust and debris with fire at his fingertips. The flames lashed out in a bright whip, catching the sleeve of Harry's robes as he dodged the hit meant for his shoulder; he tore the sleeve off before it could hinder him and boosted the smoldering fabric into a fireball lobbed back at Riddle half a second later. It was engulfed in a torrent of water before it could hit, but Harry's real goal had been to buy time for his next move -- he tossed out several dim but effective severing hexes in Riddle's direction, then holstered his wand, gathering energy in his hands.

The telltale crackling grew louder and louder, static flashing between his fingers -- Harry fell back, putting more distance between them, as he pulled his hands apart with physical effort and flung  _ lightning _ across the ring with a triumphant yell that was swallowed up by the accompanying thunderclap.

Riddle -- Merlin, he  _ caught _ Harry's lightning, pulling it into a sparking ball between his own palms, manic laughter ringing in Harry's ears, before dispersing it into the water flooding around him. Harry found himself laughing, too, pouring magic into the air beneath and ahead of him, as he made to run headfirst into Riddle's range -- then leapt  _ over _ the pools of water entirely, carrying himself on the wind.  _ This was the greatest high! _

His flying kick aimed at Riddle's chest didn't connect, of course, but Harry found he didn't care, the idea had been incredibly fun. Riddle -- no, wait, Tom, he'd asked Harry to call him Tom, Harry remembered now -- neatly sidestepped his obvious trajectory, smiling, and plucked him effortlessly out of the air and onto the floor with an expert martial arts move Harry had never seen anyone apply in a duel.

Pinning Harry on his back, the man brought the full weight of his magic to bear on him, crushing the air out of his lungs; rather than struggle back, however, Harry coiled his aura up and around Tom, not clashing but melting through and  _ into _ his professor's magic, in order to tug Tom down onto him so their bodies pressed together as well as their auras.

This close, he could see the older wizard's pupils were blown; he beamed down at Harry, resting on his elbows, then closed the last of the distance and was kissing him full on the mouth. Harry didn't do a thing to stop him, though he certainly could; in fact, he never wanted this to end.

He moaned into the kiss, intensely aware of his physical reaction to their duel -- and how, from the feel of Tom's body against his own, his professor was reacting the same way -- and spread his legs a little, the better to entangle them together, the better to grind his hips up against Tom's --

"Tell me you want this, Harry," Tom breathed against his neck, raising himself up a bit to get more leverage.

"I want it  _ so bad," _ Harry groaned, reaching up to wrap his arms around Tom's back and guide him back down.

They rutted against each other, drowning their voices in the unity of lips and tongues; who was the more desperate between them, Harry couldn't have said. He dug his fingers into Tom's shoulderblades, pulling away from the kiss to gasp out, "Tom, I'm  _ coming--" _ in the most wrecked voice he'd ever heard out of his own mouth.

_ "Harry," _ Tom growled in agreement, before they both went still with strain and let out matching sighs. The symmetry of the moment seemed only fair, when Harry was coherent enough to think about it later.

They lay, panting and sticky, on the stone floor for quite a while.

Hermione and Ron didn't end up seeing Harry again until dinner, nearly two hours later. "Hey guys," he beamed at them, piling his plate nearly as high as Ron's. "Sorry I didn't catch up. I really needed to unwind."

Hermione pointedly didn't comment on the fact that Harry had obviously just showered and changed his clothes. "What did Professor Riddle want to talk to you about after class?" she asked, instead.

"Mostly about how I was behaving in class today," her friend answered between bites of roast beef. "He guessed something was bothering me, and he was right. I just hadn't realized how to address it 'til then."

The answer irked Hermione, and not out of a belief that he was lying -- in fact, knowing Harry as she did, it was clear he was being honest. It was just... the phrasing, she thought. It had to be the phrasing. "Do you still have detention, then?"

At that, Harry gave a solemn nod. "Yes, that hasn't changed. I'm not holding it against him, though. It's necessary."

"When did  _ you _ become such a goody two-shoes, Harry?" Ron chided jokingly from Hermione's left. "I don't think I've ever heard you call a detention  _ necessary." _

Harry shrugged, running his fingers through his black hair. "Exceptions can always be made." He stood from the table, plate cleared, picking up his satchel. "I'm going to head down early, see if I can hit the library before the hour changes. See you guys later."

Watching Harry leave the Great Hall at a brisk pace, it occurred to Hermione to look up at the Head Table, just in time to catch Riddle excusing himself from his plate as well. The man looked... younger, now that she was paying attention to it. Livelier.

"Ron," she whispered, "I think they really  _ were _ kissing earlier."

The door to Riddle's -- Tom's, Harry reminded himself -- quarters opened soundlessly to admit him, onto a large, comfortable main parlor with low-backed leather armchairs and a crackling fire in the hearth. A curved stone archway gave Harry a view of the next room, a spacious kitchen, where the professor currently stood pouring out cups of tea for both of them. "Sit anywhere you like, Harry," Tom called. "Would you like any cream?"

"Any amount is fine," Harry replied, looking around. For rooms in a dungeon, the professor's quarters had a lot of elegantly carved wood, well-polished to a gleam in the firelight. Arches of flowers, snakes coiled on branches, the odd skull in a burst of leaves; the style was simultaneously opulent and cozy, like coming home.

Tom seated himself in the armchair across from Harry's, floating the tea set down onto the table between them. Harry raised his eyebrows at the scent wafting off the cups -- it was clearly tea, but it smelled like chocolate. "I don't think I've ever had this kind before," he murmured, taking an appreciative sniff.

"It is a rarer blend, but all the more valuable for its rarity," Tom smiled, sipping his with a contented expression. "Rather caffeinated, as well, so neither of us finds his eyes closing before they ought to." He offered a small, suggestive smirk that Harry found himself instantly matching; Harry took a long drink from his cup, a bit of foaming cream lingering on his upper lip. He licked it off deliberately slowly, glancing up to meet Tom's eyes, and crossed his legs in his seat to hide the way his trousers were beginning to constrict him.

In contrast, his professor let his legs splay out, unashamed to show off the way Harry was affecting him. "I must say, Harry," he purred, "this afternoon was most enlightening. Have you always had such a way with wandless, wordless magic?"

"As long as I can remember, yes," Harry replied, his eyes lingering on the bulge in those dark trousers. He lifted the teacup to his lips again to hide the way he was beginning to salivate over it. "I never get to use it in duels, though. They're over too quickly."

"I am sorry for them," Tom mused, "for lacking my... stamina."

"Not  _ too _ sorry, though, I hope," Harry rejoined, privately proud of himself for keeping his voice steady. "After all, it means you get to be the first."

He was still unable to tear his eyes from Tom's trousers, but he could imagine all too well the expression that accompanied that hitched breath, and visible twitch underneath the fabric. "Oh,  _ Harry," _ the man sighed, "am I really?"

"Maybe I've been waiting for the right wizard to come along," Harry supposed, finally raising his gaze to meet Tom's. The  _ look _ he was getting from the man made his cheeks flush, despite himself, and he uncrossed his legs, giving up the attempt to disguise his interest.

"I have been waiting for someone like you for a very long time," Tom said, his voice gone low with unapologetic desire.

"Someone like me?" Harry bit his lip, glancing to the side.

"A worthy opponent," Tom elaborated. "A match. One who could be my equal."

A crease marred Harry's brow. Those words were oddly familiar, but why..? "What do you mean?" he asked, jarred from the moment.

Tom blinked, then smirked more broadly, licking his lips. "An equal," he reprised his words, "or one might say, 'one with the power to defeat me.' For you see, Harry," he leaned forward, leering at him, and the next words came out in a soft breath like a hiss. "Hogwarts' current Defense Professor is the Dark Lord Voldemort."

Harry's eyes went wide as he felt the subtle lightening of a weight that marked a shared Fidelius secret. He glanced up at the wood carvings, again. Snakes. Skulls.  _ Oh. _ Heat pooled low and deep within him.

"It's... exciting, to be recognized for one's talents," Harry suggested. "And to recognize talent in others in turn." He set his empty teacup down on the table. "To be  _ seen," _ he continued, "when all the world is blind."

The slow smirk that spread across Tom's face set his eyes aglow in the firelight. Between one blink and the next, the gaze lingering on Harry, trailing up and down between his face and his tenting trousers, was a vivid, ruby red. "Isn't it?" Tom agreed.

Harry wasn't even mad about the Fidelius. "That was incredibly clever of you," he had to admit. "Tom Marvolo Riddle - 'I am Lord Voldemort' - and all of Dumbledore's lessons about you, all of sixth year, and nobody can even think to connect the dots."

"Flattery will get you everywhere, Harry," Tom hummed, licking his lips. Harry had to avert his eyes back to the straining black fabric of Tom's trousers to keep from leaking in his own. His fingers twitched with the idea of feeling that substantial erection under his hand; of unbuttoning the trousers and sliding his fingers in to grasp —

"I... I don't think I've ever been more aroused in my life," Harry breathed. "I'm not sure what to do about it."

Tom's interested expression gave way to one full of overt desire, and he rose from his seat to stand before Harry. "Arousal," he breathed, "the most paralyzing hunger." He leaned in closer, looming over Harry where he sat, and his gaze nearly burned. "What do we know of hunger, dear Harry?" A beat. "It needs to be fed."

He went gracefully to his knees, then, and laid his hands on Harry's thighs.

"Oh," was all Harry could say, as a heated shudder went through him like ripples in a pool. "Am I... feeding you? Or are you... feeding me?"

"Yes, I think, is the answer to that," Voldemort smiled, and leaned in to trace his mouth against the aching bulge in Harry's pants.

Harry moaned, unable to help himself, and threw his head back over the armchair, fingers digging into the leather upholstery. The Dark Lord held him down with one hand on his thigh, while the other deftly unfastened the buttons on his trousers, and reached in to take Harry in hand the way Harry had imagined doing for  _ him. _ Exposed to the air, the droplet of fluid welling at the tip left a cool trail down the side -- until,  _ "oh," _ it was wicked away by the tip of a hot tongue.

Voldemort wasted no time in swallowing Harry down; the feverish heat that spread over Harry's skin in waves was nearly as painful as the actual pain he would have expected from being touched, in a different way. When he tangled his fingers in the Dark Lord's hair, unable to help himself, he was rewarded by a pleased hum that he felt all the way at the base of his cock -- and the light scrape of teeth against the shaft as he pulled back, the better to suck Harry down again.

_ "Aah," _ the moan tore from Harry's throat, his back arching. He gasped for breath, reflexively attempting to thrust in, but found every attempt held back by the hand on his hip. "It's -- it's  _ too good!" _ It was as if he were waist-deep in a pool of scalding water, just this side of enjoyable, and sinking deeper by the second. "I want," Harry groaned, "I want to do this for you. To --  _ ah _ \-- taste you on my tongue like this."

Soft laughter reverberated through Harry's entire being; he curled his toes, feeling the muscles of his legs tensing.  _ "Please," _ he sobbed. "Let me... let  _ me..." _

But there was to be no respite, it seemed, until Harry came. And he ran out of words to say shortly after, as the Dark Lord lavished attention on the sensitive spot just under the head, tongue pressing into the slit to taste him, before taking him to the root again in a single stroke. Harry was melting, his vision going white around the edges. He let out a last, weak cry, going limp, and came so hard that he actually passed out.

**Notes for the Chapter:**

> The chocolate tea mentioned in the fic is a real tea -- I bought a tin from a French shop a while back as a gift for someone, and they liked it quite a bit. Give it a try!
> 
> Original prompt: Sylveon♥kami, 2019/06/22: Tom Riddle is the DADA professor, but his classes are rarely actually about DADA. Most of the time, he’s recounting his personal experiences and expects the class to study by the book. Harry always stops to argue with Riddle, even when his friends tell him to stop, because Riddle will just increase their homework. Harry just doesn’t listen, and after one entertaining but fruitless argument between Harry and Tom, Professor Riddle assigns him detention after class, to teach him some manners. Of course, Harry is fucked.


End file.
